Coping is formed on the top of a body in order to have a width corresponding to a transverse width of a bridge for supporting a girder in the top of a pier. Previously, after assembling and installing mould on the top of the bridge and pouring concrete while gradually constructing the bridge from the bottom of the bridge in place, concrete is cured and the coping is built on the top of the pier by disassembling the mould.
Meanwhile, the construction of bridges due to cast-in-place concrete has been less used for the reasons of the long period of construction, environmental problems, and civil complaints caused by environmental problems. Instead, the method for quick assembling and constructing pre-formed segments in a construction site has been widely used.
The fast construction method has been appearing as an alternative in that not only can the whole period of bridge construction be reduced, but environmental problems and civil complaints can be minimized. Also, it is true that the fast construction method helps construction environment mechanized by using large equipment.
There are advantages in which since a unit structure manufactured as a precast type, i.e., a segment, is manufactured in a uniform place and the quality of concrete is easily maintained, it is easy to maintain high-quality members; since segments are continuously manufactured, it is easy to control manpower and be used for mould only; and since segments may be manufactured with base construction, air may be cut as compared with the cast-in-place method.
If the assembling method is used, the bridge is constructed by gradually lifting up and assembling the pier body and the coping, manufactured with a plurality of segments, with cranes after building base concrete in which base sites are dug from the surface of the ground in place.
As above, in case that bridges are constructed by the assembling method, the body and the coping, composed of each unit structure, are lifted up by cranes and therefore, it may be much safer as self weight is getting reduced.
Therefore, the method for reducing the weight of the segment has been mainly studied. However, even though the weight of the segment is decreased, bearing capacity or seismic performance of the assembled bridges should not be diminished.
Especially, as for bridges, since a post and a coping are mainly affected by compressive load and bending load, respectively, the size of the side of the coping is generally large. Also, since the coping is usually more than a minimum of 10 meters long, the total weight of the coping is commonly quite heavy.
Therefore, the way to sharply reduce the self weight of the coping should be found out in order to seek the assembly bridge constructing method. As for girders, the size of the load for the coping is approximately 500 tons, five times of the size of the load for each girder, whereas the size of the load for each girder is generously approximately 100 tons. Therefore, the size of the side of the coping should be extremely bigger than that of the girder.
For this reason, the weight of the coping must be extremely large and therefore, the way to reduce self weight has been studied for fragmenting the coping.
To solve the above problem, a lightened coping for bridge was invented.
As illustrated in FIG. 1, the lightened coping for bridge (30) is composed of: a vertical wall (31) to which a plurality of steel wires (33) and a hollow pipe (35) are inserted in a longitudinal direction; and a support (32) to which one side of a plurality of the girders (40), protruded from the bottom of the vertical wall (31) in right and left direction, is installed. Especially, H beam (34) is inserted in a longitudinal direction of the vertical wall (31) in the position in which the vertical wall (31) is faced in the support (32) (i.e., the bottom of the vertical wall (31)), and a plurality of girder supports (32a, 32b, 32c) in the side, protruded in right and left direction from the support (32), are mutually and independently protruded. One side of the girder (40) is installed on the girder supports (32a, 32b, 32c) independently protruded in right and left direction.
However, it is difficult for the lightened coping for bridge to be moved after manufacture because the width of the coping of the lightened coping for bridge is the same as that of the bridge. Also, it is impossible to be applied except small-sized bridges due to its weight.